Almost all passenger transport vehicles have exterior lights. They are provided for a wide variety of different purposes, such as for allowing the passengers and/or operators to view the outside, for passive visibility, for signalling purposes, etc. In the aircraft industry and other fields, exterior lights are highly regulated in terms of the light intensity distributions that are emitted from the lights.
LED light units have become common in the aircraft industry in recent years. In order to satisfy the regulations, complex optical structures have been developed that comprise various LED's, reflectors and shutters. These complex structures lead to LED light units that are complicated to manufacture and are fairly costly.
Accordingly, it would be beneficial to provide an LED light unit that has improved means for conditioning the output light intensity distribution. Further, it would be beneficial to provide a method of replacing existing LED light units, for example when they are used for a long time or broken, with such improved LED light units, while keeping the wiring of the power supply systems.